Chickenpox begins to spread throughout South Park, and infects Stan's sister Shelley and Kenny. The other boys' mothers begin to think that maybe the other boys should be exposed to it too, so as to get it while they are young and it is easier to deal with. They agree and have the other boys stay over at Kenny's house. The boys are less than enthusiastic about spending the night over at Kenny's because he is so poor, comparing his home to a third-world country when they discover rats, a black-and-white television, and a ColecoVision game system; even the dinner served there is a meager waffle per person with no side dishes. The next day, Cartman and Stan get sick, but not Kyle. Stan's chickenpox gets so bad he has to be brought to the hospital with Shelley. Mrs. Broflovski tries sending Kyle over to Kenny's house again, much to Kyle's protests; she even invents a game for Kyle and Kenny to play called "Ooky Mouth", which involves Kenny spitting in Kyle's mouth while Kyle tries to say "Ooky Mouth". Cartman becomes unable to handle the itchiness from the pox and becomes intrigued and relieved when his mom gives him calamine lotion, despite her warnings of not to use too much.

Meanwhile, Mrs. Broflovski, after learning from Mrs. McCormick that her husband, Mr. McCormick, and Gerald, Mrs. Broflovski's husband, had once been close friends, decides to try to patch things up between them by setting them both up on a fishing trip. However, the trip does not work out too well and the two men come to blows. Apparently, Mr. McCormick is jealous of Gerald Broflovski's success, while Gerald makes a speech to Kyle about how some people need to be poorer than others as part of a capitalist society, what he calls the hierarchy of "gods and clods." As part of his homework assignment, this makes Kyle come up with a plan to eliminate all the clods in the world to make it a better place - by putting them in camps; this makes Gerald realize the callousness of his beliefs.

After Kyle learns from his mom that she tried to get him sick, he breaks Stan out of the hospital. Both go to Cartman's house to retrieve Cartman and all of the boys decide to get revenge on the adults for what they did. The parents begin a frantic search, while the boys go see Old Frida, a local prostitute with herpes in her mouth, and pay her to go to their homes and lick, touch and otherwise mess with the parents' stuff to give them all herpes. The parents find the children and bring them back to the hospital; at this point Kyle finally falls ill and passes out on the floor, making Sheila realize what a horrible thing she has done.

All the boys wind up in the hospital, and the parents get herpes; they agree it a was fair revenge for what they had tried to do and everyone heartily laughs, even when Kenny (who also ended up at the hospital) dies.